1. Field of the Invention
The present invention relates generally to a speaker system and, in particular, relates to a speaker system in which both the heat radiation of the power amplifier and satisfactory acoustic characteristics can coexist.
2. Description of Related Art
For some time, speaker systems in which a speaker is mounted in a speaker box having an interior air space formed therein have been known. These speaker boxes may have an opening for heat radiation provided in the front surface of the speaker box. The opening allows the heat that is generated by the speaker to be exhausted to the outside of the speaker box. With this kind of speaker system, because an opening for heat radiation is provided in the uppermost portion of the speaker box, it is possible for the air that is warmed and rises to be exhausted (radiated) from the opening to the outside of the speaker box with satisfactory efficiency. An example of such a speaker system is disclosed in Japanese Unexamined Patent Application Publication (Kokai) Number 2001-346283 (See, for example, paragraph 0017, FIG. 1.)
In those cases where the speaker that has been mounted in a speaker box that has an interior air space formed therein is driven by a power amplifier, speaker systems that have the power amplifier deployed in the interior air space of the speaker box are preferred. This is because of carrying convenience and the like.
However, a considerable amount of heat is produced by the power amplifier when the speaker is driven. This heat, if it is confined within the box, can undesirably cause failures or faulty operation of the speaker. In this case, as has been disclosed in the above-mentioned reference, the heat can, to some extent, be radiated to the outside by providing an opening for heat radiation in the speaker box.
However, the technology that is disclosed in the above-mentioned reference has as its aim the exhausting of the heat that is produced by the speaker to the outside of the speaker box. The radiation of the heat that is produced by a power amplifier is not even considered. Because of that, in those cases where an amplifier has been deployed in the interior air space of the speaker box, there is a problem in that the heat radiating ability is insufficient and the heat cannot be fully radiated. As a result, there have been failures and faulty operation of components in the speaker box. In addition, it has been difficult to satisfy the temperature requirements that are prescribed by the safety standards of various countries.
It is possible to improve the design of the speaker box to increase the heat radiating ability, for example, by making the area of the opening larger. However, in those cases where the area of the opening is made unreasonably large, the acoustic characteristics of the speaker system are impaired.
In addition, the user may come in contact with high temperature electronic circuits by, for example, reaching through the opening. This creates an unsafe condition for the user.